Shaft for screw-propellers.



No. 759,726. PATENTED MAYlO, 1904. H. S. MAXIM.

$HAPT FOR SCREW PROPELLERS.

APPLICATION FILED NOV.16. 1903.

N0 MODEL. 3 SHEBTS-SHEET 1.

0 a w /z' VQ li/mm di/i'axwz No. 759,726. PATENTED MAY 10, 1904.

H. S. MAXIM.

SHAFT FOR SGREW PROPELLERS.

APPLIOATIOII FILED NOV. 16. 1903.

N0 MODEL. 3 SHEETS-SHEET 2.

Zfla$zezsveaX 20822 Z02 PATENTED MAY 10, 1904.

11.3. MAXIM.

SHAFT FOR SCREW PROPELLERS.

APPLIOATION TILED NOV. 16. 1903.

3 SHEETE-HHEET 3.

H0 MODEL.

wZzwueJ/ iZW/Z 0) Ji m W awzkzz KJ/ d 21 UNITED STATES Patented. May 10, 1904.

PATENT OFFICE.

HIRAM STEVENS MAXIM, OF "WEST NORWOOD, ENG-LAND.

SHAFT FOR SCREW-PROPELLERS.

SPECIFICATION forming part of Letters Patent N0. 759,726, dated May 10, 1904.

Application filed November 16, 1903. Serial No. 181,357. (No model.)

To all whom 71']; may concern:

Be it known that I, HIRAM Srnvjnns MAXIM, Chevalier of the Legion of Honor, civil, electrical, and mechanical engineer, a subject of the King of Great Britain, residing at Thurlow Lodge, Norwood Road, Test Norwood, in the county of Surrey, England, have invented certain new and useful Improvements Relating to the Shafts of Screw-Propellers, of which the following is a specification.

This invention relates to the shafts of screwpropellers, and has for its chief object to overcome the liability of these shafts to fracture or breakage while in use. It is generally admitted by engineers that the breakage of screw-propeller shafts is due almost entirely to some fleXure of the ship which throws the shaft out of alinement. The screw-propeller shafts of large steamships are necessarily made of considerable diameter and of steel of such nature that it is not very elastic, so that it does not require that these large shafts should be much out of alinemcnt to render them liable at each rotation thereof to be bent sufficiently to bring the external layer of steel beyond its ultimate elastic limit. The steel in this way soon becomes fatigued and cracks commence at the outside and work inward. It has been found on many occasions that the shaft is perfectly in alinement when the ship is unloaded, but that it is thrown out of alinement by leading the ship or even by shifting the cargo. Then again in a heavy sea the thin afterpart of the ship springs or vibrates to the right and left, and as the shaft is much thicker than the hull of the ship the springing or vibration, which does not at all injure the hull, might prove sufficient to cause the shaft to crack. Furthermore, it often happens that some of the bearings wear out of alinement, and this again subjects the shaft to bending. It is generally conceded by engineers that the frequent breakage of shafts at sea is due to their being out of alinement, and many attempts have been made to devise some sort of universal coupling that would be flexible enough to allow the shaft to bend at the couplings instead of at the part between the couplings.

It is the chief object of my invention to de vise a coupling of this kind which shall possess the requisite strength and flexibility without occupying more or little more space than an ordinary coupling and which shall also be comparatively easy to manufacture. c i

According to my invention 1 make the shafting in suitable lengths and provide their meeting ends with hemispherical or other suitablyshaped flanges forged thereon, said flanges en gaging with each other by teeth or projections and being coupled together by an external sectional casing kept in place by bolts passing through said casing and the flanged ends of the shafting. The aforesaid flanged ends of the shafting, the external casing, and the bolts are so constructed and arranged, as hereinafter described, that the coupling constitutes a species of ball-and-socket joint.

In order that my said invention may be clearly understood and readily carried into effect, I will describe the same more fully with reference to the accompanying drawings, in which Figure 1 is a longitudinal section of one form of the coupling, in which the aforesaid flanged ends of the shafts are of hemispherical shape. Fig. 2 is a face view of one of the flanged ends. Fig. 3 is a longitudinal section, and Fig. t an end view, of a modified form of said coupling, in which only one of the flanged ends is of hemispherical shape. Fig. 5 is a longitudinal section, and Fig. 6 an end view, of a modified form of the coupling illustrated by Figs. 3 and 4:. Figs. 7 to 10 illustrate couplings similar to that shown by Figs. 5 and 6, but having the m'ojections on the ineetingfaces of the flangedshafts diflerently formed, Figs. 7 and 8 being sectional elevations, and Figs. 9 and 10 face views, of.

A A are the flanged ends of two lengtl s of the shafting to be coupled, said fianged'ernls being made integral with the shafts by a forgmg or similar operation. a w are the teeth or projections which are formed on the meeting surfaces of the said flanged ends. C is the sectional casing. Referring more particularly to Figs. 1 and Q, the flanged ends A A are each made of hemispherical shape with their flat surfaces facing each other, so that when brought together they form an approximately spherical joint. On the meeting surfaces of the said hemispherical portions are formed the afore- Said teeth or projections to a, which in this case are radial. These teeth or projections engage and serve to transmit the rotary movement of one length of shafting to the other, and they permit deviations in the alinement of the shafting to take place without becoming disengaged. Within the hollow interior portions of the hemispherical ends A A a hardened metallic body B is placed, said body being in this example of spherical shape and composed of hardened steel. This body serves to receive the end thrust on the shafting, so as to render the teeth or projections a a unaffected by said thrust. The casing C is composed of several sections, in the present case four sections 0 c c 0', the two sections 0 0 to gether forming one half of the casing and the two other sections 0 0 together forming the other half of the casing. The said sections of one half of the casing are so arranged that their meeting edges lie in a plane at right angles to that ofthe meeting edges of the other section. The internal shape or contour of the said casing is similar to that of the exterior of the flangedends A A. The portions of the sections 0 c surrounding thecylindrical part of the shaft just behind the hemispherically-flanged end A of the latter are made with an internal diameter somewhat greater than the diameter of the shaft they surround, and also, if desired, somewhat conical or tapered, so as to be of greater diameter at the outer than at the inner end. I thus provide for the movement of the adjacent ends of the shafting relatively to each other. The meeting faces of the two halves of the casing are flanged at 0 8, one of the said faces being advantageously formed with an annular groove toflt a corresponding rib on the other face. A washer or washers may be interposed between these meeting faces. 0 c are the bolts that pass through the body portion of the said sections 0 0 and also through the flanged ends of the shafting, the bolt-holes in one of said ends (or it may be in both of said ends) being made of larger diameter than the bolts, and, if desired, also tapered, so as to permit of the flexibility of the coupling without impediment from the said bolts. Lateral rigidity is imparted to the coupling by means of annular plates or disks C C, covering the outer ends of the sections 0 c and maintained in place by the said bolts 0 Each of these annular plates or disks 0' G is made in halves and the meeting edges are arranged to lie at right angles to the meeting faces of the sections 0 0 or c c of the casing 0, as shown in Fig. 4.

The above-described manner of connecting together the various sections of the aforesaid casing imparts great rigidity thereto and yet insures that the coupling shall have perfect freedom of movement in order to compensate for any inequality in the alinement of the shafting. It also enables a symmetrical form of the coupling to be obtainedthat is to say, both of the meeting ends of the shafting and coupling are identical in appearance. The coupling also occupies very little space.

In the modified arrangements illustrated in Figs. 3 and 4 and in Figs. 5 and 6 only one of the flanged ends of the shafting is made hemispherical, the outer end being cylindrical. In these examples also the hardened-steel body B is of mushroom shapethat is to say, it has a hemispherical head with a tail Z), and the interior surfaces of the meeting ends of the shafting are correspondingly formed to receive said hardened body. i

In Figs. 3 and 4 the sectional casing C is somewhat similar in construction to that shown in Figs. 1 and 2, excepting that the section 0 is of cylindrical shape internally to conform to the cylindrically-flanged end of the shafting it surrounds. Also in this case the end plate C of the sections 0 c of the easing has a flange C which engages with a cylindrical groove or recess in the said sections 0 0, thereby imparting extra rigidity to the coupling. The said-plates C are made in halves, as aforesaid, with their meeting edges at right angles to the longitudinal meeting faces of the sections of the casing, Fig. 4. Bolts 0 passing through the casing, the end plates, and the flanged endsof the shafting, retain the parts of the coupling together, as explained in connection with Figs. 1 and 2.

In Figs. 5 and 6 the adjacent ends A A of the shafting are formed like those shown in Figs. 3 and 4; but the portion 0 of said sectional casing C is dispensed with, the cylindrically-flanged end of the shafting being suitably formed to abut against the meeting edge of the portions 0 of said casing. In this case, therefore, the said casing C is composed of only two segmental sections. The end plate 0 has a flange C and is 'made in halves, as in Figs. 3 and 4, bolts c serving to connect the parts of the coupling together, as above described. This last-mentioned arrangement of the coupling is very suitable for use where the available space for the coupling is limited, as it will occupy no more space than the form of coupling now generally used with screwpropeller shafting.

In the arrangements shown by Figs. 7 to 10 I have illustrated a coupling similar to that of the kind last above described, but in which the projections a on the adjacent faces of the flanged ends of the shafting are more conveniently made than in the preceding arrangements above described. The projections shown in Figs. 7 and 9 are adapted to be made in a lathe or boring-machine and those shown in Figs. 8 and 10 are adapted to be made in a slotting-machine. In Figs. 7 and 9 the said. projections a are in the form of a circular scries of cylindrical bosses on one of the flanged endsof the shafting, said bosses loosely fitting corresponding recesses formed. in the other flanged end of the shafting. Both the projections and the recesses are formed with holes for the bolts 0 to pass through.

In Figs. 8 and 10 the projections a are in the form of segments obtained by transversel slotting the face of one of the flanged ends in directions at right angles to each other, the other flanged end being formed with correspending recesses for the loose reception of the segmental projections.

I am aware that screw-propeller shafts have already been made with universal couplings, some of which may have proved satisfactory when it was not necessary to forge flanges on the shafting. The chief novel feature of my invention that my coupling can be employed advantageously with shafting in which the flanges are solid therewith. As a matter of fact no other form of screw-propeller shafting is permissible nowadays in powerful steamships.

In the above description of my invention I have set forth number of forms of my coupling with the object of illustrating sev eral constructions thereof to enable those having various kinds of tools to make the coupling. For instance, the form in which the projections a are cylindrical, Figs. 7 and 9, can be made in a boring-machine and the form shown in Figs. 8 and 10 can be made in a slotting-machine, as stated above. I prefer, however, the kind of coupling which can be made in a milling-machine, Figs. 1 to 6; but millingmachines large enough to effect this kind of work are not easily obtained at the present time.

The modifications of the coupling shown in Figs. '7 to 10 are quite easy to manufadture with the ordinary tools mentioned above. .In the early days of screw-propellers the shafting was generally driven by a single double-acting cylinder. It therefore followed that each time the crank reached the dead-center the screw-propeller and other moving parts carried the crank over the said center by their momentum. In such case if there were much backlash or looseness of the coupling or its connections a violent and destructive pounding of the parts was obtained; but in all of the large steamships of the present day more than one cylinder is employed, generally three are employed, so that there is a constant and uniform torsion on the shafting at all times. Therefore it is not necessary that the couplings should be made so that they may be absolutely free from backlash. The devices which .1. have shown can be made so that each particular coupling will not be loose to a greater extent than the ten-thousandth part of an inch, and this is not enough in any way to affect the working of the engine. The only time that any backlash will make itself apparent is when the engine is suddenly reversed while going at full speed ahead. This is an event, however, that does not occur very often in the life of a steamship. It is therefore not necessary to have any apparatus for taking up the lost motion in my coupling.

hat 1 claim, and desire to secure by Letters Patent of the United States, is-- l. ,l n a shaftcou1 )ling, the combination with the shaft-secti 1)ns having flanged ends and engaging projections on the adjacent faces of said flanged ends, of means for resisting the end thrust between said adjacent faces, a sectional casing inclosing said flanged ends, and bolts extending longitudinally through the casing and the flanged ends for the purposes specified.

2. ln a shaft-coupling, the combination with the shaft-sections having hemisphericallyflanged ends and engaging projections on the adjacent faces of said flanged ends, of means for resisting the end thrust between said adjacent faces, a sectional casing inclosing said flanged ends, segmental end plates for said casing, and. bolts extending through the easing, the end plates, and the flanged ends of the shafting for the purposes specilied.

3. .11] a shaft-coupling, the combination with the shaft-sections having hemis )hericallyflanged ends and engaging projections on the adjacent faces of said flanged ends, of a spherical body located between said adjacent faces, a sectional casing formed of two transverse halves each composed of two longitudinal halves, a rib on one of the transverse halves engaging with a corresponding recess in the other transverse half, end plates made in halves with their abutting edges lying in planes at right angles to the meeting faces of the longitudinal halves of the casing, and bolts extei'lding through the casing, the end plates and. the flanged ends of the shafting substantially as described.

a. In a slnift-coupling, the combi nation with the shaftsections having liemisphericallyflanged en s and engaging radial teeth on the adjacent faces of said flanged ends, of a spherical body located between the adjacent faces, a sectional casing formed of two transverse halves each composed of two longitudinal halves, a rib on one of the transverse halve." engaging with a corresponding recess in the other transverse half, end plates made in hal vcs with their abutting edges lying in planes at right angles to the meeting faces of the longitudinal halves of the casing, and bolts extending through the casing, the end plates and the flanged ends of the shafting substantially as described.

5. In a slnift-coupling, the combination with the shaft-sections lravinghemispherically and cylindrieall y flanged ends and engaging projections on the adjacent faces of said flanged. ends, of means for resisting the end thrust be- Ibo tween said adjacent faces, a sectional casing fitting around said flanged ends and having a recess, segmental end plates for said casing, one of said plates provided with a flanged periphery adapted to engage in said recess in the sectional casing, and bolts extending through the casing, the end plates, and the flanged ends of the shafting substantially as described.

6. In a shaft-coupling, the combination with the shaft-sections having hemispherically and cyl indricall y flanged ends and engaging radial teeth on the adjacent faces of said flanged ends, of means for resisting the end thrust located between the adjacent faces, a sectional casing formed of two transverse halves each composed of two longitudinal halves, one of said sections of said casing provided with a rib and the other with a-recess adapted to receive said rib, end plates made in halves with their abutting edges lying in planes at right angles to the meeting faces of the longitudinal halves of the casing, one of said plates provided with a flanged periphery adapted to engage in the said sectional casing, and bolts extending through the easing, the end plates and the flanged ends of the shafting substantially as described.

7. In a shaft-coupling, the combination with the shaft-sections having hemispherically and cylindrically flanged ends provided with a recess and engaging projections on the adjacent faces of said flanged ends, means for resisting end thrust between said adjacent faces, asectional casing around said flanged ends and provided. with an annular projection at one end thereof fitting said recess in the cylindrically-flanged ends of the shaft-sections, a segmental end plate at the opposite end of the casing and provided with an annular projection fitting in the casing, and bolts extending through the casing, the end plate and the flanged ends of the shafting substantially as described.

8. In a shaft-coupling,the combination with the shaft-sections having hemisphericall y and cylindrically flanged ends one of which having recesses and a circular series of cylindrical projections on the face of one flanged end adapted to engage in said recesses, of means for resisting end thrust between said adjacent faces, a casing formed of two longitudinal halves fitting around the flanged ends and provided with an annular projection at one end thereof fitting inthe cylindrically-flanged ends of the shaft-sections, an end plate formed in halves and located at the opposite end of said casing with the meeting edges of its halves lying at right angles to the meeting faces of the sectional casing and provided with an annular projection fitting in the casing, and bolts extending through the casing, the end plate and the flanged ends of the shafting substantially as described.

9. Inashaft-coupling, the combination with the shaft-sections having hemispherically and cylindrically flanged ends one of which is provided with a series of recesses and the other of which with a circular series of projections engaging in the recesses of the other end, of means for resisting end thrust between said adjacent faces, a casing formed of two longitudinal halves fitting around the flanged ends and provided with an annular projection at one end thereof fitting in the cylindricallyflanged ends of the shaft-sections, an end plate formed in halves and located at the opposite end of said casing, with the meeting edges of its halves lying at right angles to the meeting faces of the sectional casing and provided with an annular projection fitting in the easing, and bolts extending through the casing, the end plate and the flanged ends of the shafting substantially as described.

In testimony whereof I have hereunto set my hand, in presence of two subscribing wit nesses, this 4th day of November, 1903.

HIRAM STEVENS MAXIM.

. WVitnesses:

T. SELBY VVARDLE, IV M. M ELLoRsH-J ACKSON. 

